Assessing the effects of plant species, functional traits, and groups on soil microbial diversity

Soil microbes are crucial to mediating multiple ecosystem services and processes. However, manipulating the soil microbiome to reliably enhance the desired ecosystem services remains challenging. Inclusion of plant functional traits (PFTs) in understanding the effects of plant diversity on the soil microbiome might provide a path forward in designing plant communities as lever to alter soil microbial communities. Through this study, we sought to elucidate if the differences in PFTs corresponded to the differences in their associated soil microbiome. The plant species in our study spanned six taxonomic families exhibiting a wide range of growth forms, life forms, and rooting habits. A total of 29 distinct plant species, with five individuals each were grown in a randomized complete block design under greenhouse conditions. At the end of six weeks, individual pots were destructively sampled for characterizing PFTs and soil microbial communities. Our research revealed that differences in plant attributes, including species identity, functional groups and traits corresponded to differences in both alpha and beta diversities of soil microbial communities. Moreover, differences in soil bacterial community structure were primarily driven by plant biomass and root C:N ratios while individual bacterial taxa were more strongly correlated with root morphological traits. Also, soil bacterial communities differed more in response to the variation in plant functional traits than fungal communities in a short time (six weeks). These results indicate that plant functional traits could help better predict soil microbial community structure; however, more research is needed to assess how these relationships scale up to an ecosystem level.